Most in-ground swimming pools have two or more return lines either on the wall of the pool (generally about 6 inches below the tile line) or along the floor (as with in-floor cleaning systems), or with the latter, a wall return port may also be included such as near the steps.
For conventional wall return ports, the return is a fixed unit, which is only a cover or collar insert for the PVC pipe entering into the pool, with a smaller aperture or orifice to inject water into the pool in one fixed direction or a manually adjustable fixed direction.